Kata Kunci : Kadar Air, water Content, Microwave, Distilasi, Desikator
Penentuan kadar air bisa dilakukan dengan berbagai cara :
Penentuan kadar air bisa dilakukan dengan berbagai cara :
- Pengeringan Cara Biasa Memakai Oven / Microwave
Caranya : sampel dipanaskan di oven / microwave
beberapa lama menggunakan rentang suhu 100 - 102 C shg air teruapkan.
Perhitungan kadar air adalah sampel awal ditimbang
(a), sesudah dipanaskan dan diperkirakan air sudah teruapkan ditimbang (b),
maka kadar air = ((a - b) / a) x 100%
"Determination water content can be
done with various methods :
- Normal drying using oven / microwave
Method : the sample is heated in oven /
microwave several time use temperature range 100 - 102 C so water is
evaporated. Calculation water content was first
sample is weighed (a), after it is heated and it is estimated water already is
evaporated and be weighed (b), so water content = ((a - b ) / a) x 100%
"
- Metode Distilasi
Caranya : sampel yg mengandung air ditambahkan larutan
yg mempunyai titik didih lebih tinggi daripada air dan massa jenis yg lebih
rendah daripada air utk mempermudah pemisahan walau titik didih rendah dan
massa jenis tinggi juga bisa dilakukan, tapi utk mempermudah pemisahan cara yg
umum dipakai adalah itu, (contohnya toluene, xylene) kemudian dilakukan
distilasi pada suhu 100 - 102 C shg air teruapkan dan diembunkan di kondensor,
maka liquid akan tertampung pada corong pemisah dan dapat dipisahkan air dengan
larutan yg ditambahkan tsb, dimana air akan berada di layer bawah karena massa
jenis yg lebih besar. Lalu dilakukan penimbangan berat.
Perhitungan kadar air adalah sampel awal sebelum
ditambah larutan ditimbang (a) dan air distilat ditimbang (b), maka kadar air =
(b / a) x 100%
- Distillation method
Method is sample contain water added to
solution have higher boiling point than water and lower density than water to
easy separation, however low boiling point and high density also can be done,
but to easy separation so commonly use is that (eg toluene, xylene) then
distillation at temperature 100 - 102 C and water is evaporated then be
condensed in condensor. Liquid is contained in separation funnel and can be
separated water with that solution. Water will place in low layer due to large
density. Then do the weighing. Calculation water
content is weighing first sample before added solution (a) and distillate water
is weighed (b) and water content = ( b / a) x 100% "
- Pengeringan dengan Desikator
Caranya : sampel diletakkan di desikator. Desikator
adalah alat yg tertutup terbuat dari kaca yg didalamnya ada bahan (desikan)
yg bisa menyerap air dari udara. Macam desikan yg sering digunakan adalah :
> CaCl2, P2O5,
ZnCl2, H2SO4, CaSO4, KOH, BaO, Al2O3,
P2O5 dan silica gel.
Dari sekian banyak desikan yg sering digunakan adalah silica
gel. Dimana prinsip pengeringan dan perhitungannya adalah mula-mula wadah
sampel kosong di oven 100 - 105 oC (sekitar 3 jam) utk menghilangkan
air kemudian didinginkan dlm desikator utk menghilangkan total air,
dihitung beratnya (a). Kemudian sampel dimasukkan ke wadah tadi (b) lalu
dimasukkan ke desikator utk beberapa waktu (sekitar 12 - 24 jam) lalu
diambil dan sampel tadi ditimbang (c), maka kadar air = ((b - c) / (b - a)) x
100%.
Desikan yg digunakan adalah silica gel dan
indikasi bahwa silica gel menyerap air adalah perubahan warna dari
mula-mula biru menjadi merah muda (tanda sudah menyerap air).
Silica gel dapat digunakan kembali dengan
mengeringkan di oven / microwave pada suhu 100 - 105 oC.
Indikator bahwa pengeringan optimum adalah perubahan warna dari merah muda
menjadi biru (sekitar 3 - 6 hari), waktu ini sebenarnya bukan menjadi patokan
tapi yg menjadi referensi adalah perubahan warna, jadi saat sudah berubah warna
menjadi biru hentikan pemanasan karena banyak faktor yg mempengaruhi waktu
seperti kandungan air dan volume silica gel.
- Drying using Desiccator
Method : the sample is placed in the
desiccator. Desiccator is close instrument, made from glass and inside there is
drying agent (desiccant), have function absorb water from air. The kinds of
desiccant commonly use are
> CaCl2, P2O5,
ZnCl2, H2SO4, CaSO4, KOH, BaO, Al2O3,
P2O5 and silica gel
From many kinds desiccant often is used, there is silica gel. Drying and calculation principle is initially empty container is heated in oven / microwave 100 - 105 C (about 3 hours) to remove water then be cooled in desiccator to remove total water, calculated weight (a). Then sample is entered to that container (b) then entered to desiccator for several time (about 12 - 24 hours) and taken then sample is weighed (c), so water content = ((b - c) / (b - a)) x 100%
Desiccant used is silica gel, and indication silica gel absorb water is color change from blue to pink (sign containing water).
From many kinds desiccant often is used, there is silica gel. Drying and calculation principle is initially empty container is heated in oven / microwave 100 - 105 C (about 3 hours) to remove water then be cooled in desiccator to remove total water, calculated weight (a). Then sample is entered to that container (b) then entered to desiccator for several time (about 12 - 24 hours) and taken then sample is weighed (c), so water content = ((b - c) / (b - a)) x 100%
Desiccant used is silica gel, and indication silica gel absorb water is color change from blue to pink (sign containing water).
Silica gel can be reused with drying in
oven / microwave at temperature 100 - 105 C. Optimum drying is color change
from pink to blue (about 3 - 6 days), this time no reference but reference is
colour change, so if occur blue colour change stop heating. Many factors affect
heating time such as water content and volume of silica gel "
 |
| Silica Gel |
 |
| Desikator |
ARTIKEL TERKAIT :
1. Tentang Microwave "Oven"
2. Desain Kolom Pemisah Distilasi
3. Macam - Macam Proses Pemisahan (Separation Process)
Previous
« Prev Post
« Prev Post
Next
Next Post »
Next Post »